English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Tools annual

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Presents the access of premium content as premium feature

Premium Content

Global: Zendy Plus annual

Global: Zendy Free Plan

Background  Xylose isomerase (XI) and xylose reductase/xylitol dehydrogenase (XR/XDH) pathways have been extensively used to confer xylose assimilation capacity to  Saccharomyces cerevisiae  and tackle one of the major bottlenecks in the attainment of economically viable lignocellulosic ethanol production. Nevertheless, there is a lack of studies comparing the efficiency of those pathways both separately and combined. In this work, the XI and/or XR/XDH pathways were introduced into two robust industrial  S. cerevisiae  strains, evaluated in synthetic media and corn cob hemicellulosic hydrolysate and the results were correlated with the differential enzyme activities found in the xylose-pathway engineered strains.    Results  The sole expression of XI was found to increase the fermentative capacity of both strains in synthetic media at 30 °C and 40 °C: decreasing xylitol accumulation and improving xylose consumption and ethanol production. Similar results were observed in fermentations of detoxified hydrolysate. However, in the presence of lignocellulosic-derived inhibitors, a positive synergistic effect resulted from the expression of both XI and XR/XDH, possibly caused by a cofactor equilibrium between the XDH and furan detoxifying enzymes, increasing the ethanol yield by more than 38%.    Conclusions  This study clearly shows an advantage of using the XI from  Clostridium phytofermentans  to attain high ethanol productivities and yields from xylose. Furthermore, and for the first time, the simultaneous utilization of XR/XDH and XI pathways was compared to the single expression of XR/XDH or XI and was found to improve ethanol production from non-detoxified hemicellulosic hydrolysates. These results extend the knowledge regarding  S. cerevisiae  xylose assimilation metabolism and pave the way for the construction of more efficient strains for use in lignocellulosic industrial processes.

biotechnology for biofuels

Xylose fermentation efficiency of industrial Saccharomyces cerevisiae yeast with separate or combined xylose reductase/xylitol dehydrogenase and xylose isomerase pathways